Category: Colorism (page 2 of 2)

Skin Color is Not Driving the Relationship Between Racial Admixture and IQ

Some variables in the Add Health and the NLSY97 allow us to investigate the relationship of skin color with IQ and racial ancestry with IQ (AHPVT scores and ASVAB scores) among the US black population. Given the positive results, a question worth considering is whether or not skin color mediate the relationship between family ancestry and IQ.

Continue reading

HVGIQ: Cayman Islands

The Cayman Islands is a British Overseas Territory. In global comparison, this tiny dependency ranks near the top in standard of living and per capita GDP (currently sandwiched between the U.S., Ireland, Japan and Iceland). Lynn and Vanhanen’s books include data for Bermuda—another Overseas Territory—but do not mention the Cayman Islands.

At least one psychologist has administered intelligence tests to Cayman Islands school children (1960 Curti ), and this forgotten study is noteworthy because it is also one of the relatively rare instances where black and white IQ scores have been compared outside of the United States, Britain, and South Africa. Continue reading

More than Just “Colorism”: Part 1.

The meaning of a Jensen Effect on the Color Effect

Dalliard showed that IQ correlates with color in both the American Black and Hispanic populations (a color effect) and, importantly, that the IQ-color correlations are positively related to a subtest’s general intelligence loading (a Jensen effect). In short, he showed that there was a Jensen effect on the IQ color effect. This is significant for reasons elaborated elsewhere. Generally, if an IQ difference is strongly positively correlated with g – is g(+) – biological causation is implicated; alternatively, if an IQ difference is strongly negatively correlated with g – is g(-) – cultural causation is implicated. Here, “biological causation” refers to psychophysiological influences on mental states that do not act through sensory informational pathways, while “cultural causation” refers to psychophysiological influences on mental states that act through these pathways; as an example of the general biological versus cultural causal schema, with respect to personality, differences induced by pharmacological agents would be classed as “biological causal” while differences induced by psychotherapy would be classed as “cultural causal.” This schema, of course, isn’t perfect – but it has utility and is not infrequently employed in psychology.
Continue reading

Spearman’s hypothesis and the NLSY97-ASVAB, part 2

Skin color is a (very imperfect) proxy for white ancestry in African Americans and Hispanics. If racial and ethnic gaps in intelligence have a genetic component, we would expect lighter skinned individuals to have higher IQs, on the average. Further, because g is the main heritable component of intelligence, tests with higher g loadings should show larger associations with skin color.

We investigated these hypotheses in the NLSY97 sample. It contains interviewer reports on facial skin tone of the respondents as measured on a scale of 1 (lightest) to 10 (darkest). The interviewers used a “color card” as a reference.

All the correlations below are significant at conventional levels unless otherwise indicated. Because of the way skin color is coded in this analysis, negative correlations between skin color and test performance are expected if the hereditarian hypothesis is correct.

I found that among blacks, the correlation between g scores and skin color (darkness) was -0.133 (N=1856), whereas T scores were unrelated to skin color (r=-0.012, ns; N=1856). Among Hispanics, g scores correlated with skin darkness at -0.123 (N=1051), while T scores were unrelated to skin color (r=0.062, ns; N=1051). Therefore the results are about as expected. (See the previous post for information about the T factor.)

Applying again the method of correlated vectors (MCV), we found that vectors of skin color-test gap correlations were strongly and significantly associated with g loadings within populations. In other words, lighter-skinned individuals tended to outscore darker-skinned coracials/coethnics more on tests with higher g loadings. Among blacks, the correlations were r=-0.84 and rho=-0.75, and among Hispanics r=-0.60 and rho=-0.59 (correcting for unreliability would make all these correlations somewhat stronger).

The MCV results could be interpreted in terms of genetic effects: tests with higher g loadings are more heritable, and skin color is a proxy for white ancestry and thus presumably better “IQ genes”. But why would these within-population color analyses produce the expected correlations between g loadings and race markers (i.e., skin tone) when the between-population MCV analysis, presented in the previous post, did not? It appears that on the ASVAB g is the major source of racial/ethnic differences, but the T factor also contributes to the gaps. (Cohen’s d’s on the g scale were B-W 1.124, B-H 0.368, and H-W 0.759, while on the T scale they were B-W 0.561, B-H 0.261, and H-W 0.306.) However, T is not associated with skin color within populations, which suggests that its heritability is low and it is linked to race and ethnicity for non-genetic reasons. This would explain why the MCV results from within- and between-population analyses differ.

In the NLSY97, higher g is associated with lighter skin among blacks and Hispanics. This is in accord with hereditarian theory, but nurturists would of course argue that these correlations are due to colorism. These competing hypotheses could be tested by comparing skin color-IQ associations within and between families, as was done here.

Newer posts

© 2017

Theme by Anders NorenUp ↑